Summer of Science: How many people would fit into Australia?

How many people would fit into Australia?

A reader asked: How many people can fit into Australia?

This is an interesting question because there are so many different ways to answer it.

But, since it's the silly season, let's really massage our imaginations first.

The most efficient way to fit people into Australia is to make them all stand together - shoulder to shoulder, back to front, like standing sardines.

According to the body proportions detailed by American sculptor Avard Fairbanks, the adult male has a shoulder length of about 45.7 cm and an adult female of about 36.6cm.

Because the dimensions of a male and female adult human differ slightly, we've based our calculations on a 50:50 ratio of males to females. Australia is 7.69 million km2, so if we use the human sardine model we'd fit 39 trillion people into Australia - if we accept there's some fancy footwork at play that allows people to walk on water (that is, to stand on lakes and rivers).

But that's not enough.

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What if we stacked people on shelves? If each shelf was 2 metres tall and we stacked them all the way up to the edge of space, we could add 3000 times more flat-packed humans - and fit a whopping 117 quadrillion people into the country.

You'll have spotted the small problem here: the sardine solution (single or stacked) won't be acceptable under free-range chicken rules, where there can only be 10,000 hens per hectare.

Based on this, we could only fix approximately only 7.69 trillion humans and remain within legal free-range limits - but at least it would be an ethical approach (and more likely to produce good-quality eggs).

But - getting to the important point - the issue is whether or not Australia could sustain all those people. People need resources - like food, water and space - so that's a bigger limiting factor than space alone. Australians consume a lot of resources, even though Australia is very large.

"If everyone in the world started living and consuming and producing waste like an average Australian then it would take the equivalent of four planets Earth to sustain them," says Gour Dasvarma, Associate Professor of Population Studies at Flinders University.

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"[But] considering all possibilities it may be stated that about 40 million people could live in Australia.

"Of course, this does not mean Australians should go on consuming more and creating more waste; on the contrary Australians should strive to reduce their ecological footprint in consideration of the worsening climate crisis of the world."

Just out of interest: what if Australia's population was merely the equal of one the world's most population-dense places? Let's choose Singapore, which has a population density of more than 8000 people per square kilometre (let's call it 8000 - easier maths).

That density would have Australia's population at about 63.7 billion people: not as many as our sardine solution, but still more than eight times the Earth's current population. Ouch.

  • These articles are published in partnership with Cosmos Magazine. Cosmos is produced by The Royal Institution of Australia.

ACM has partnered with Cosmos, Australia's only independent science newsroom, to fulfill your curiosity and help to answer those curly science questions.